Display screen or portion thereof with a graphical user interface



The sole FIGURE is a front view of a display screen or portion thereofwith a graphical user interface, showing our new design.

The broken line showing a display screen with graphical user interfaceis included for the purpose of showing portions of the article whichform no part of the claim.

CLAIM We claim the ornamental design for a display screen or portionthereof with a graphical user interface, as shown and described.